Mirrors are often accompanied by a light to illuminate a person's face as he/she looks in the mirror. Such lights are often disposed above or to the side(s) of the mirror, resulting in shadows on the person's face.
Cosmetic mirrors exist that consist of a small mirror with a light disposed on or near the outer perimeter of the mirror. These mirrors are typically much smaller than a wall mirror and often are disposed on a stand to make them portable, thus taking up space on a vanity or counter.
Backlit mirrors that distribute light around the outer perimeter of a mirror from behind a mirror centered in an enclosure, require a relatively deep concave surface behind the mirror, which limits the mirror and enclosure to a circular shape and limits the ratio of the mirror size and enclosure size.